Coordinated parking-monitoring system

ABSTRACT

The present invention discloses a coordinated parking-monitoring system. A co-monitored parking space is monitored by at least two parking-monitoring devices. Its effective parking-monitoring area is substantially more than that if it were monitored by a single parking-monitoring device. This lowers the overall system cost.

BACKGROUND 1. Technical Field of the Invention

The present invention relates to the field of electronics, and moreparticularly, to a parking-monitoring system.

2. Prior Arts

Locating a vacant parking space causes much frustration to motorists. Itincreases fuel consumption and has a negative impact to the environment.To conserve energy resources and enhance the quality of the environment,it is highly desired to develop a parking-monitoring system, which cantransmit substantially real-time parking occupancy data to motorists.Based on the parking occupancy data, a motorist can be guided towards avacant parking space at destination.

Parking enforcement is an important aspect of city management. Thecurrent parking-enforcement system is patrol-based, i.e. parkingenforcement officers patrol the streets and/or parking lots to enforcethe parking regulations. This operation requires significant amount ofman power and also consumes a lot of fuel. It is highly desired to takeadvantage of the above-mentioned parking-monitoring system andautomatically measure the parking time for each monitored parking space.

Both parking monitoring and enforcement are based on the detection ofparked vehicles (i.e. parking detection). Because it can monitor a largenumber of parking spaces simultaneously, a camera is an ideal device forparking detection. Prior arts disclose many camera-basedparking-monitoring systems. FIG. 1A discloses a cross-sectional view ofa camera-based parking-monitoring system. A parking-monitoring device 25a captures the images of the parking spaces 05 d . . . along the curb 20a of the street 20. It is mounted on a support 21 a such as an utilitypole or a street-lamp post, which also provides power to the device 25a.

FIG. 1B discloses a top view of the camera-based parking-monitoringsystem. In prior arts, each parking space is monitored by a singleparking-monitoring device. Due to its finite view angle 22 a (limited bya right edge 23 a and a left edge 24 a), the parking-monitoring device25 a can monitor a finite number (a total of seven in this example) ofparking spaces 05 a, 05 b . . . 05 g. These parking spaces 05 a-05 gform a monitored group 30A for the parking-monitoring device 25 a.Likewise, an adjacent parking-monitoring device 25 b monitors sevenparking spaces 05 h, 05 i . . . , which form a monitored group 30B. Inprior arts, there is no overlap between the monitored groups 30A and30B.

FIG. 1C discloses more details of the parking spaces 05 g, 05 h near theborder between the monitored groups 30A and 30B. When a vehicle isparked in the parking space 05 g, it will occlude a portion of itsadjacent parking space 05 h from the perspective of theparking-monitoring device 25 a. Out of the total parking area (denotedby “ABCD”) of the parking space 05 h, only the shaded portion (denotedby “EBCF”) is an effective area which can be used for parking monitoring(i.e. effective parking-monitoring area). When its effectiveparking-monitoring area ratio, i.e. the ratio between the effectiveparking-monitoring area (“EBCF”) and the total parking area (“ABCD”), isbelow a parking-determination threshold (e.g. 70%), the effectiveness ofthe parking-monitoring device 25 a to monitor the parking space 05 hbecomes questionable. As a result, the parking space 05 g becomes therightmost parking space that can be monitored by the parking-monitoringdevice 25 a. Line 23 a becomes the right edge of the view angle 22 a,which bounds the monitor group 30A of the parking-monitoring device 25a.

The prior-art parking-monitoring system is an un-coordinatedparking-monitoring system: each parking-monitoring device works byitself and there is no coordination among them. As a result, the parkingspaces that can be monitored by each parking-monitoring device arelimited. This increases the total system cost.

Objects and Advantages

It is a principle object of the present invention to conserve energyresources and enhance the quality of the environment.

It is a further object of the present invention to lower the overallsystem cost of a parking-monitoring system.

It is a further object of the present invention to increase the numberof parking spaces that can be monitored by each parking-monitoringdevice.

In accordance with these and other objects of the present invention, acoordinated parking-monitoring system is disclosed.

SUMMARY OF THE INVENTION

The present invention discloses a coordinated parking-monitoring system.Different from prior arts where each parking-monitoring device works byitself and each parking space is monitored by a singleparking-monitoring device, at least a parking space is monitored by atleast two parking-monitoring devices. This parking space is referred toas a co-monitored parking space. The effective parking-monitoring areaof the co-monitored parking space is substantially more than that if itwere monitored by a single parking-monitoring device. As a result, thenumber of parking space that can be monitored by a parking-monitoringdevice increases (e.g. from seven to eight). This helps to lower theoverall system cost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a cross-sectional view of a city street monitored by aparking-monitoring device; FIG. 1B is a top view of the city streetmonitored by an un-coordinated parking-monitoring system (prior art);FIG. 1C illustrates the effective parking-monitoring area of a parkingspace monitored by a single parking-monitoring device (prior art).

FIG. 2A is a top view of the city street monitored by a preferredcoordinated parking-monitoring system; FIG. 2B illustrates the effectiveparking-monitoring area of a co-monitored parking space, which ismonitored by two parking-monitoring devices.

FIG. 3A is a block diagram of a preferred coordinated parking-monitoringsystem; FIG. 3B is a block diagram of a preferred parking-monitoringdevice.

FIGS. 4A-4B are flow charts of two preferred coordinatedparking-monitoring methods.

It should be noted that all the drawings are schematic and not drawn toscale. Relative dimensions and proportions of parts of the devicestructures in the figures have been shown exaggerated or reduced in sizefor the sake of clarity and convenience in the drawings. The samereference symbols are generally used to refer to corresponding orsimilar features in the different embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Those of ordinary skills in the art will realize that the followingdescription of the present invention is illustrative only and is notintended to be in any way limiting. Other embodiments of the inventionwill readily suggest themselves to such skilled persons from anexamination of the within disclosure.

Referring now to FIG. 2A, a preferred coordinated parking-monitoringsystem deployed in the city street 20 is disclosed. This coordinatedparking-monitoring system comprises at least a co-monitored parkingspace 05 h, which is monitored by two parking-monitoring devices 25 aand 25 b. The monitored group 30A* of the parking-monitoring device 25 aincludes the parking spaces 05 d, 05 e, 5 f, 05 g, 05 h, . . . , whilethe monitored group 30B* of the parking-monitoring device 25 b includesthe parking spaces 05 h, 05 i, 05 j, 05 k, . . . . Compared with FIG.1B, the parking space 05 h, instead of the parking space 05 g, becomesthe rightmost parking space that can be monitored by theparking-monitoring device 25 a. The view angle 22 a* of theparking-monitoring device 25 a becomes larger and its right edge 23 a*extends to the parking space 05 h. Likewise, the view angle 22 b* of theparking-monitoring device 25 b also becomes larger and its left edge 24b* extends to the parking space 05 h. In the example disclosed in FIG.1B and FIG. 2A, the total number of the parking spaces monitored by eachparking-monitoring device 25 a, 25 b increases from seven to eight.

FIG. 2B discloses more details of the parking spaces 05 g, 05 h, 05 inear the border between the monitored groups 30A* and 30B*. For theco-monitored parking space 05 h, the first effective parking-monitoringarea for the first parking-monitoring device 25 a is the area “EBCF”,whereas the second effective parking-monitoring area for the secondparking-monitoring device 25 b is the area “HEI” (excluding theoverlapped area between “HBCG” and “EBCF”). Because the parking space 05h is co-monitored by the parking-monitoring devices 25 a and 25 b, thetotal effective parking-monitoring area for the co-monitored parkingspace 05 h is the sum of the areas “EBCF” and “HEI”, which is shown inthe shaded area “HBCFI”. Accordingly, the total effectiveparking-monitoring area ratio, i.e. the ratio between the totaleffective parking-monitoring area (“HBCFI”) and the total parking area(“ABCD”), becomes higher than the parking-determination threshold (e.g.70%). Hence, the parking space 05 h, although it cannot be reliablymonitored by the parking-monitoring device 25 a in prior arts, can bereliably monitored in the coordinated parking-monitoring system.

Referring now to FIGS. 3A-3B, a preferred coordinated parking-monitoringsystem is disclosed in FIG. 3A. It comprises a first parking-monitoringdevice 25 a and a second parking-monitoring device 25 b. The firstparking-monitoring device 25 a communicates information 40 with thesecond parking-monitoring device 25 b. In one preferred embodiment, thecommunicated information 40 includes the images of the parking space 05h. In another preferred embodiment, the communicated information 40includes the occupancy likelihood of the parking space 05 h.

FIG. 3B is a block diagram of a preferred parking-monitoring device 25.It comprises an image-capturing means 70, an image-processing means 80and a communication means 90. The image-capturing means 70 couldcomprise at least one camera. When it comprises multiple cameras, thesecameras may face different directions in such a way that a large numberof parking spaces can be monitored simultaneously. The image-processingmeans 80 could comprise a processor and a memory. The processor could beany type of central-processing unit (CPU), graphic-processing unit (GPU)and/or digital signal processor (DSP). The memory used by theparking-monitoring device could be any type of non-volatile memory (NVM,e.g. flash memory) or hard-disk drive (HDD). It could store an operatingsystem of the parking-monitoring device. The communication means 90could be Bluetooth, WiFi or cellular communication means.

Referring now to FIGS. 4A-4B, two preferred coordinatedparking-monitoring methods are disclosed. In the preferred method ofFIG. 4A, the first parking-monitoring device 25 a captures the images ofa first plurality of parking spaces, including a first image of theparking space 05 h (step 100). At the same time, the secondparking-monitoring device 25 b captures the images of a second pluralityof parking spaces, including a second image of the parking space 05 h(step 200). Then the first parking-monitoring device 25 a transfers thefirst image of the parking space 05 h to the second parking-monitoringdevice 25 b (step 120). The second parking-monitoring device 25 bdetermines the occupancy of the parking space 05 h from the first andsecond images of the parking space 05 h (step 220).

FIG. 4B is a flow chart of a second preferred coordinatedparking-monitoring method. The first parking-monitoring device 25 acaptures a first image of the parking space 05 h (step 100), while thesecond parking-monitoring device 25 b captures a second image of theparking space 05 h (step 200). Afterwards, the first parking-monitoringdevice 25 a does a preliminary processing on the first image of theparking space 05 h. Because its first effective parking-monitoring ratiois below the parking-determination threshold from the perspective of thefirst parking-monitoring device 25 a (FIG. 1C), this preliminaryprocessing can only obtain a first occupancy likelihood for the parkingspace 05 h (step 140). The first occupancy likelihood could be the ratioof the first changed area (i.e. the area within the first effectiveparking-monitoring area “EBCF” which has a background change) and thetotal parking area “ABCD”. Similarly, a second occupancy likelihood canbe calculated from the perspective of the second parking-monitoringdevice 25 b (step 240). Then the first parking-monitoring device 25 atransfers the first occupancy likelihood to the secondparking-monitoring device 25 b (step 160). The second parking-monitoringdevice 25 b determines the occupancy of the parking space 05 h from thefirst and second occupancy likelihoods (step 260). For example, thefirst occupancy likelihood is 0.6 and the second likelihood is 0.2, bothof which are below the parking-determination threshold (0.7). The totaloccupancy likelihood is 0.8 (0.6+0.2), which is above theparking-determination threshold. A hard occupancy decision hereby can bemade. Because only the first occupancy likelihood (no the first image)is transferred, a smaller communication bandwidth is required for thecommunication means 90.

While illustrative embodiments have been shown and described, it wouldbe apparent to those skilled in the art that many more modificationsthan that have been mentioned above are possible without departing fromthe inventive concepts set forth therein. The invention, therefore, isnot to be limited except in the spirit of the appended claims.

1-20. (canceled)
 21. A coordinated parking-monitoring method, comprisingthe steps: A) a first camera-based parking-monitoring device including afirst camera obtains a first occupancy likelihood of a co-monitoredparking space from a first image captured by said first camera; B) asecond camera-based parking-monitoring device including a second cameraobtains a second occupancy likelihood of said co-monitored parking spacefrom a second image captured by said second camera; C) said firstcamera-based parking-monitoring device transfers said first occupancylikelihood of said co-monitored parking space to said secondparking-monitoring device; D) said second parking-monitoring devicedetermines the parking occupancy of said co-monitored parking space fromsaid first and second occupancy likelihoods.
 22. The coordinatedparking-monitoring method according to claim 21, wherein said firstcamera-based parking-monitoring device transfers said first occupancylikelihood to said second parking-monitoring device with at least acommunication means.
 23. The coordinated parking-monitoring methodaccording to claim 22, wherein said communication means is a Bluetoothcommunication means.
 24. The coordinated parking-monitoring methodaccording to claim 22, wherein said communication means is a WiFicommunication means.
 25. The coordinated parking-monitoring methodaccording to claim 22, wherein said communication means is a cellularcommunication means.